Going Beyond the Causal Limit in Acoustic Absorption

Mak, Ho Yiu; Zhang, Xiaonan; Dong, Z.-C.; Miura, Susumu; Iwata, Takuro; Sheng, Ping

doi:10.1103/physrevapplied.16.044062

Cited by 18 publications

(8 citation statements)

References 44 publications

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“…This feature of soft-boundary reflection problem enables designs of space-saving absorbers in the ultra-low-frequency range. In [47], a specific design has been proposed and validated experimentally.…”

Section: Fundamental Constraints For Unidimensional Scattering Problemsmentioning

confidence: 99%

Fundamental constraints on broadband passive acoustic treatments in unidimensional scattering problems

et al. 2022

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In a passive lossy acoustical system, sum rules derived from passivity explicitly relate the broadband response to the spatial dimension of the system, which provide important design criteria as well. In this work, the theory of Herglotz function is applied systematically to derive sum rules for unidimensional scattering problems relying on passive acoustic treatments which are generally made of rigid, motionless and subwavelength structures saturated by air. The rigid-boundary reflection, soft-boundary reflection and transmission problems are analysed. The derived sum rules are applied for guiding the designs of passive absorbers and mufflers: the required minimum space is directly predicted from the target (i.e. the desired absorption or transmission-loss spectra) without any specific design. Besides, it is possible to break this type of sum rules and fundamental constraints in particular cases. This property, if well used, could result in ultra-compact absorbers working at long wavelength up to infinity.

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Section: Fundamental Constraints For Unidimensional Scattering Problemsmentioning

confidence: 99%

Fundamental constraints on broadband passive acoustic treatments in unidimensional scattering problems

et al. 2022

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“…[1][2][3][4][5] However, it is really noises in the low-frequency regime that are the most difficult to be eliminated. Governed by the general rules of linear response, 6 commercial sound-absorbing materials, such as foams, fabrics, and panels, are inherently weak in attenuating lowfrequency (< 1.0 kHz) acoustic waves owing to their long wavelengths and strong penetrating capacities. Through advanced materials synthesis, novel foam materials have been proposed as sound absorbers.…”

Section: Introductionmentioning

confidence: 99%

Multifunctional sound-absorbing and mechanical metamaterials via a decoupled mechanism design approach

Wang

et al. 2023

Mater. Horiz.

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“…Numerous researchers have attempted to achieve subwavelength acoustic structure design within the con nes of the minimum thickness limit [23][24][25][26][27][28][29][30][31][32][33][34] . Recently, Mak et al [35] used a soft boundary to circumvent the minimum thickness…”

Section: Introductionmentioning

confidence: 99%

Deep Subwavelength Broadband Sound Absorption by a Buckled Plate Resonator

Han

Xing

2023

Preprint

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The absorption performance and the sample thickness need to satisfy the causal relation, and the sound absorption bandwidth of a thin layer structure is often very narrow to achieve high sound absorption at low frequency. In this paper, a buckled plate resonator is proposed to achieve the low frequency broadband sound absorption in the deep subwavelength range. The resonator consists of an air-tight back cavity sealed by an elastic circular thin plate. A uniform in-plane compressive force is applied on the thin plate to make the plate buckling produce negative stiffness, and the resonator operates in the pre-buckling state. By adjusting the structural stiffness, the buckled plate resonator achieves the purpose of adjusting Beff and B0, which weakens the causal principle requirement of minimum acoustic structure thickness and realizes broadband low-frequency sound absorption. The final experimental results show that one 3mm(λ/220) back cavity, 0.89 sound absorption is achieved at 515Hz, and the corresponding relative sound absorption bandwidth is 19.4%. From the causal relation, the calculated minimum sample thickness is 6.7mm for the observed absorption spectrum. Compared with traditional plate-type acoustic metamaterials, which achieve low-frequency sound absorption by increasing the mass, the absorption bandwidth is too narrow due to the influence of the quality factor Qm, our work provides a design paradigm for the low frequency broadband acoustic absorbers.

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Going Beyond the Causal Limit in Acoustic Absorption

Cited by 18 publications

References 44 publications

Fundamental constraints on broadband passive acoustic treatments in unidimensional scattering problems

Fundamental constraints on broadband passive acoustic treatments in unidimensional scattering problems

Multifunctional sound-absorbing and mechanical metamaterials via a decoupled mechanism design approach

Deep Subwavelength Broadband Sound Absorption by a Buckled Plate Resonator

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